1. Filed of the Invention
This invention relates to an automatically interchangeable type wheel type printing apparatus. Vertically moving members contain a plurality of type wheels in a type wheel containing housing which movably mounted on a carrier, a desired type wheel is moved to a position suitable for printing.
2. Related Background Art
There have existed printers which has a plurality of type members each provided with a plurality of printing types and each continuing printing while automatically interchanging the type members. Such devices are disclosed, for example, in U.S. Pat. No. 4,357,115, U.S. Pat. No. 4,281,938, U.S. Pat. No. 4,026,403 and Japanese Patent Application Laid-Open No. 58-39464.
However, these printers are not always satisfactory from the viewpoint of high-speed printing. So, to solve this problem, in Japanese Patent Application No. 60-177754 (U.S. application Ser. No. 896,056 filed on Aug. 13, 1986) there has been proposed a printer designed such that a plurality of disc-like type wheels are carried on a carriage and a desired type wheel is automatically mounted by a wheel interchanging mechanism provided on the carriage.
Further, in Japanese Patent Application No. 61-168289 (U.S. application Ser. No. 73,216 filed on Jul. 14, 1987) there has been proposed a printer in which an interchanging mechanism for mounting or dismounting type wheels carried on a carriage at a printing position or therefrom and a mechanism for moving an ink ribbon up and down are operated by a common drive source to thereby reduce the number of parts and lighten the carriage.
In this type of automatically interchangeable type wheel printing apparatus, when the vertically moving member of a type wheel is to be moved vertically, the opposite ends of the vertically moving member of the type wheel have been driven by a belt a lever or the like through engagement members, but the driving device for the vertical movement of the vertically moving member of such a type wheel is complex and increases the production cost and in addition, increases the weight and volume of the carrier, and this has proved a hindrance to improved printing speed and compactness of the apparatus, particularly, small height of the entire apparatus.